I have no dash lights or warning lights at all-the only light that lights up anywhere on the dash is the left turn signal arrow. My fuse box has power but the 3A instrument cluster fuse blows the instant I turn on the headlight switch (which I recently replaced). I noticed that I get conductivity across that fuse's terminals when the fuse is not installed-is that normal? Also, today I took the dash apart and the wiring appeared intact, the bulbs looked good, and I didn't see any breaks in the printed circuit board. I cleaned the contacts before I reinstalled the harness. I must say the whole set-up with the printed circuit board seems very flimsy though, and the instrument cluster plate is very brittle. Would replacing these two items be the next logical step or is my short coming from somewhere else? I read on this forum that aftermarket stereos can cause a short in the instrument light circuit if the blue/red wire was connected to ground, but under the dash I disconnected this wire from the stereo harness (there was a plug) and it didn't solve the problem. If you have any ideas, please let me know-I'm willing to try anything before I have to order a bunch of expensive new parts. Thanks!

 

Insp all the wiring bundles associated with the dash lights. I'd find the short before buying new stuff.

Headlight switch is a common problem, and the turning signal switch also. (yes I see you already replaced the headlight one).

Look for any modded or spliced wiring harnesses for extra lights, stereos, amp, speakers, cab lights ect...

Insp all wiring bundles for damage, kinks, cuts, bend, smashes, burnt on exhaust system, rat/mice chew marks ? I would look under the hood at the head light wiring (there is a separate wire run for each headlight) I suspect damage in there.

Insp down the frame towards the back end, inside the dvrs side frame rail for something rubbing on a bundle.

You have a hot wire with damage getting grounded out, since you are blowing a fuse when you turn on the head light switch.

Yes brittle dash cluster is common.

 

Hey thanks for the ideas and things to check-I will take it apart again this weekend. One of the things I should have done the first time I had it apart is checked for power at the plug end of the harness, or see if the fuse still blows when the harness is unplugged. I've already gone through a box of little 3A fuses and the parts store doesn't stock them! The rest of the truck's lights all work fine-just the dash lights are out.

 

Glad your not 'upgrading' to a 30A fuse!

not related to OP's post, but FYI the headlight switch has a breaker or two in it...

 

ok, so I have the dash apart again and with the main harness unplugged from the dash cluster I still blow the fuse. Also, no matter which blue/red wire I test, I get continuity to ground (even with the switch off). I don't see any damaged wires either. This short is proving hard to find!